Alzheimer's disease is expected to mushroom in the coming
decades, as the population ages and medical advances prolong life.
The fear of this disease, of losing one's mind and presumably
one's dignity, focuses public attention on research into this field -
- but results come bit by bit, and are difficult to interpret.
As it stands today, there is no proven way to reduce risk of
Alzheimer's disease. However, several lines of evidence point to a
few preventive strategies that are largely safe.
Alzheimer's disease seems to be mostly caused by the accumulation
of proteins around neurons called "amyloid plaques." These plaques
in turn seem to be largely caused by inflammation and associated
oxidative stress. What causes the inflammation is open to question;
in fact it may be many causes that lead to the same place.
Most cases of Alzheimer's are sporadic; the disease tends not to
run in families. However, there is a genetic component to the risk,
probably involving many genes. Someday there may be genetic
screening tests (for good or for ill), but there's nothing you can
do about your genetics right now.
Other risk factors include a low educational level, head injury,
eating a diet high in calories and saturated fat and low in folate,
and a sedentary lifestyle. Most of these things involve increased
inflammation and oxidative stress.
Risk factors are not necessarily causes. Windshield wipers are on
when it rains, but it doesn't mean they cause the rain. Still, a
number of lines of evidence suggest that changing these risk factors
and related things might reduce the chances of Alzheimer's.
Cognitive stimulation is one: learning new things later in life,
exposing yourself to new situations. By doing this you're using your
brain's ability to change and grow, which works in the opposite
direction from the deterioration of dementia.
In terms of diet, fewer calories and less saturated fat might be
helpful for preventing Alzheimer's, and certainly will improve
cardiovascular risk anyway. Food causes oxidative stress; eating
anything actually stresses the body with toxic processes. One
epidemiologic study has suggested that eating fish or taking
supplemental fish oil may help.
You should probably use dietary changes or supplementation to
increase your intake of vitamins C and E, and of folate, because
deficiencies can lead to inflammation and oxidative stress. The
exact dose you would need is not certain; reasonable doses might be
vitamin C 500 milligrams twice a day, vitamin E 400 units once a
day, and folate 1 mg once a day. Vitamin E is actually used in
higher doses to treat dementia and has a modest positive effect.
The anti-cholesterol drugs called "statins" might protect against
Alzheimer's, probably through their effects against inflammation.
Most doctors would not consider preventing Alzheimer's a good reason
to start taking one, but if your cholesterol is up anyway, this can
be added motivation.
The same is true for aspirin and naproxen (Naprosyn): if you have
another reason to take these drugs, you might be getting some extra
benefit in preventing Alzheimer's. They are used to treat pain, but
they reduce inflammation also.
There is some talk of reducing blood levels of copper and iron.
These elements contribute to oxidative stress, and excess levels can
be toxic. For example, excess iron absorption causes
hemochromatosis, a very-difficult-to-diagnose disease that is
actually rather common, at 1 percent of the population.
One interesting avenue of research currently looks at
immunization against the plaque protein that causes Alzheimer's. By
stimulating the body's immune system to attack these proteins,
scientists hope that Alzheimer's can be prevented and even treated.
From a practical perspective, remember that Alzheimer's disease
currently can be diagnosed only by a pathologist looking at tissue
from a biopsy or an autopsy.
That means the diagnosis of "Alzheimer's type dementia" must
always be handled with suspicion: is the dementia being caused, or
contributed to, by something we can fix? Books have been written on
this subject, but three things are very important to exclude. Blood
tests can look for thyroid disease and vitamin B12 deficiency, and a
CT scan or an MRI can look for hydrocephalus.
Dr. Mike Merrill is an internist practicing in Buffalo. E-mail
your comments to him at driconoclast@yahoo.com.